In the past, optical disc recording media (hereinafter simply referred to as optical disc) such as BD (Blu-Ray® Disc), for example, are widely used as write-once optical recording media, which are irradiated with light and record/reproduce signals.
Some optical discs have management areas as areas used for disc management and defect management (for example, see Patent Document 1). Information for managing a recording range, in which data is recorded, is recorded in the management area.
For example, when data cannot be recorded in a recording range of an optical disc, which is specified as an area in which data is to be recorded (to be written), because of defects or another reason, alternating processing is performed. In the alternating processing, data is recorded in an alternate area, which is different from the specified area, in which the data is recorded actually.
When the alternating processing is performed, a defect list showing the recording location of the specified data and the actual recording location of the data and other information are recorded in the management area. When reading data, data is read with reference to the defect list.
Patent Document 1: Japanese Patent No. 4026517